The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC design and material have produced generations of ICs where each generation has smaller and more complex circuits than previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased.
Complementary Metal Oxide Semiconductor (CMOS) devices have typically been formed with a gate oxide and polysilicon gate electrode. There has been a desire to replace the gate oxide and polysilicon gate electrode with a high-k gate dielectric and a metal gate electrode to improve device performance as feature sizes continue to decrease. Integration issues often occur when high temperature processes are performed, especially for a metal gate. It is desired to have improvements in this area.